RejectCode

Why a host refused a joiner's AdmitMessage.Hello or AdmitMessage.Resume.

The structured companion to AdmitMessage.Reject.reason, which stays free text for humans reading a log. Before this existed a consumer had to string-match the reason to tell a transient refusal from a permanent one — and the two most consequential cases were not even distinguishable in principle, because the host sent the same words for both.

Open hierarchy (interface, not enum), mirroring us.tractat.kuilt.core.discovery.DiscoveryKind: a module outside :kuilt-session can supply its own code without amending this file. A code kuilt does not recognise — including one from a newer build, or from a peer that sends none at all — decodes as Unknown.

retryable defaults to true, deliberately. Retrying is what the joiner did before typed codes existed, so an unrecognised code preserves that behaviour exactly; only a code that explicitly declares itself terminal changes it. The dangerous direction is the other one: treating an unknown refusal as terminal would break the fast-reconnect race, where a resume that arrives before the host's detector fires is rejected and a retry a moment later succeeds.

Samples

when (reason.code) {
        // Terminal: the window closed, the credential can never validate here, or the two peers
        // speak incompatible protocol versions (retrying a version you don't support is futile).
        RejectCode.ResumeWindowExpired, RejectCode.ResumeTokenInvalid,
        RejectCode.RoomMismatch, RejectCode.ProtocolMismatch,
        -> false
        // Transient: the host hasn't opened the window yet (the fast-reconnect race).
        RejectCode.ResumeWindowNotYetOpen -> true
        // Anything else, including a code this build has never heard of.
        else -> reason.code.retryable
    }

Inheritors